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Toyota Camry harsh deceleration

00820082 Posts: 16
edited July 8 in Toyota
I have the same issue as nathan118 with my 2010 Camry. When I take my foot off the gas pedal. I feel a noticeable engine/transmission drag at about 31MPH to 19MPH. Is this normal for all Camry? Anyway to "fix" this without shifting to Neutral? Does shifting to Neutral often may shorten the life of the transmission?

Doesn't sounds like a good design to get more mileage but may prolong the brake pad a bit.

http://townhall-talk.edmunds.com/direct/view/.f10b8bd/293!keywords=allin%3Amsgte- xt%20limit%3A.ef07197%20deceleration#MSG293

Other than that, the car is very good. I don't really care about the gas pedal issue, especially I know the 2010 Camry will (or may already) have brake over-ride.
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Comments

  • petras2petras2 Posts: 104
    I experienced the same thing on my 2010 4cyl le...also noticed a similiar "drag" on my wife''s honda..I think it may be a characteristic of these new 5/6 speed automatics..the 4 spd automatics most of us used to drive didn't have this quirk..there may be a fix but I got used to it and I think it will help reduce brake wear..
  • typesixtypesix Posts: 314
    It is not just 5/6 speed automatics, owners of 4 speed automatics have also noticed the drag.
  • wwestwwest Posts: 10,706
    The "drag" is the result of the more recent adoption of an "extended" coastdown fuel-cut technique used to extend FE. The transaxle is downshifted sequentually as speed declines so that the fuel starved engine doesn't stall. Made even more noticeable with the new 6(9) speed transaxles and also since at lower speeds the transaxle goes into an upshift mode to alleviate the potential danger of FWD or F/awd engine compression braking should the roadbed be slippery.
  • 00820082 Posts: 16
    I am confused. If the purpose is to extend FE, then why I don't feel any drag when I shift to Neutral? The drag is like engine braking from the down shift.

    Neutral doesn't use any more gas than Drive, right? And the car and goes further and faster, so better FE, right? The drag is almost like a light brake is applied, similar to what many drivers do to prepare a complete stop in front of traffic light or stop sign.
  • wwestwwest Posts: 10,706
    edited March 2010
    "..The drag is like engine braking from the downshift.."

    Because that is EXACTLY what it is.

    With the fuel cut off the wheels are "driving" the engine, sort of like a trucks "jake brake". Should you put the transmission in neutral the control ECU will instantly "refuel" the engine otherwise it would stall.

    So, the choice, during coastdown, is keep the non-fueled engine running via roadway traction, or put the car into neutral and FUEL the engine.
  • 00820082 Posts: 16
    edited March 2010
    So when the wheels are driving the engine, no fuel is applied?

    If I put the car in neutral while coastdown, will I save more fuel?

    Will this practice (shift to N on coastdown) cost any more wear to the transmission?

    thanks
  • packer3packer3 Posts: 277
    Prisus any one, Monday in CA a highway runaway and just today in NY there was a runaway out of the guys driveway, who is it that said get in touch with reality Toyota is still a great car, I'm sure it was Consumer (in Toyotas pocket)Reports that made the assement. Here is reality check I would recomend people to shy away somewhat from Toyota for a few years.
    Also, who could feel safe buying a used Toyota, I'd be thinking was this one of the cars that they didn't fix?
  • 00820082 Posts: 16
    Why hijack my thread?

    I don't care about yesterday Prius report, I think it is a good opportunity for Toyota and NHTSA to prove the root cause one way or the other. As long as there is brake over-ride, I don't mind another Toyota. Remember, Toyota is not alone in reported unattended acceleration incidents, and unattended acceleration is only one problem. What's important is the overall death toll.

    What pissed me off is how Toyota handled the problem from late 2009 to January. Big mistake imo, and Toyota is now paying for it.
  • 210delray210delray Posts: 4,722
    Just leave the car in drive and let it slow down. Don't shift into neutral.
  • 00820082 Posts: 16
    packer3, you are right, we are probably from different planet. We are from Earth, the forth planet from the Sun, what planet are you coming from?

    Just to let you know. In planet Earth, it is quite impolite to jump into some one thread and spit out some off-topic comments.

    Furthermore, our apology. The runaway Prius incident you heard on Monday appears to be a hoax from the bankrupted driver Mr. James Sikes. The 911 operator repeatedly told him to put the car in neutral but he said he afraid the car would "flip". And he has a pretty bad history as well if you search his information in Business Record. So his comment is worst than Rhonda Smith who claimed at the "Congress" that her Lexus has a simultaneous failure including the transmission, the ignition system, the gas pedal, the brake. We apologize again for the stupidity of our Government of U.S.A to allow her to speak in the hearing once again.

    We should focus back to the topic now.
  • wwestwwest Posts: 10,706
    "...simultaneous failure of..."

    No, SINGLE failure, the engine/transaxle control firmware went "out to lunch".
  • 00820082 Posts: 16
    wwest, the Lexus should has hydraulic brake, right? Worst case no power assist. I can use my brake without turn on the car. There is no BBW system yet afaik.

    And the ignition is using a different system.

    btw, do you think I will save more gas by shift to Neutral during coastdown on the Camry? Will that put any meaningful wear on the transmission if I do that?

    thanks
  • 210delray210delray Posts: 4,722
    I'll give you the simple answer; he'll supply the more complicated one. ;)

    Leave the car in drive as you slow down; do not shift to neutral. You will not see a measurable difference in gas mileage either way -- other factors are much more important. Shifting into neutral will ultimately put more wear on the transmission (probably insignificant if you keep the car only a few years).
  • 00820082 Posts: 16
    edited March 2010
    many thanks. I just feel the engine drag is a bit too much but if it is "by-design", then I will accept that.

    btw, kind of off-topic. Does the Camry turn on A/C compressor when defrost is used? If yes, is there any hack to disable that?

    btw2, I don't mind to hear the more complicated answer from wwest, I really appreciate his initial explanation about the engine drag. Now I understand the purpose of the drag and that makes me feel a lot better.
  • wwestwwest Posts: 10,706
    I have sometimes wondered if our 1st gen Prius might get better FE if I modified it. Modification would consist of automatically "shifting" to neutral whenever the gas pedal returns to "idle". The Prius has no clutches to wear by shifting in and out of neutral for each coastdown period.

    At the moment the Prius will always enter regenerative braking mode during coastdown as a simulation of engine compression braking. With the automatic shift to "neutral" the car would coast farther during coastdown periods but I would be losing the recharge affect.

    6 of one, half-dozen of the other.

    Your case is simpler since you do not have a hybrid battery to recharge and so shifting to neutral would not only extend your coasting distance but also reduce the wear on the transmission via less shifting.
  • wwestwwest Posts: 10,706
    "..hack to disable that.."

    Heck, (Hack..) no. ;)

    Your dealer, as of ~'01, can set a C-best option that disables the defrost/defog/demist link that activates the A/C. I have both options set on my '01 F/awd RX300, the one above plus the one that allows me to disable the A/C indefinitely except during the summer when cooling is desireable.

    I think there are even more C-best options now, for instance one that will prevent the system from automatically shifting into cooling mode once the cabin temperature rises to your setpoint or closely nearby. The newer systems, ~2010, will also actually revert to combined footwell and defrost/defog/demist mode if climatic conditions warrant.

    My '01 Porsche C4 has a switch modification that opens the A/C compressor clutch circuit. Otherwise, going back to ~'68, I have always disconnected the A/C compressor clutch right at the clutch connection when cooling is not required.
  • 00820082 Posts: 16
    wwest,

    So in other words. If I don't mind the hassle, shifting to Neutral during coastdown is good on a 2010 Camry because of below?

    1. The fuel saved by the extended distance during coastdown should be enough to offset the small amount of duel feed to prevent the engine to stall when in Neutral.

    2. Shifting to Neutral during coastdown actually reduce the wear on the transmission because it avoid a few down-shifting.

    On a related note, many years ago, a mechanic told me shift to neutral will reduce brake distance and will not add any wear to the brake pad. Is this the same for newer engine with all the FE technology?

    Thanks

    For your Prius mod... Is there a way to detect the charge level of the battery? If the charge level exceed certain threshold (i.e. near full charged), then the car will always goes to Neutral during coastdown? I assume it is best to keep a good charge most of the time to take advantage of the hybrid technology.

    Does the Prius easy to mod? This is quite scary, I hope Toyota has protection on crucial modules (e.g. the protected codes of a Operation System).
  • 00820082 Posts: 16
    "...Your dealer, as of ~'01, can set a C-best option that disables the defrost/defog/demist link that activates the A/C..."

    Good to know. Too bad it is something has to be done by the dealer. I had a 02 Civic and I could do that myself by pressing some buttons in specific sequence, but I have no luck to find similar hack with my 2005 Pontiac Vibe and my new Camry. Also my Vibe compressor seems quite noisy compared to other cars. http://a332.g.akamai.net/f/332/936/12h/www.edmunds.com/media/townhall/webxicons/- emotorcons/emo_blush.gif
  • acco20acco20 Posts: 208
    shifting to neutral during coastdown in the hybrid models will result in additional brake use. brakes will need replacement much sooner.
  • wwestwwest Posts: 10,706
    Unless we're talking "hyper-miling" in which coastdown distances are planned. In any case the Prius brake pad seem to last so long that a little additional wear might not really matter.
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